Process and apparatus for dehydrating emulsions.



F. W. HARRIS. PROCESS AND APPARATUS FOR DEHYDRAI'ING EMULSIONS.

APPLICATION FILED mm. 191:.

'1,%81,952. Patented 001-. 15,1918.

2 SHEETS-SHEET I.

E' m LE J5 v 49 (441?! F. W. HARRIS. PROCESS AND APPARATUS FORDEHYDRATING EMULSIONS. APPLICATION FILED APR. 4. I9I7.

1,281,952. Patented Oct. 15, I918.

sion, which t ran snares are FORD W. HARRIS, OF LOS AIQIGELES,CALIFORNIA.

PROCESS AND APPARATUS FOR IDEHYDBATING- EMULSIONS.

Specification of Letters Patent.

Application filed April 4, 1917. Serial No. 159,768.

My invention relates to the art of removing water from emulsions of oiland Water, or, as it-is commonly called, to the art of dehydratingemulsions. Petroleum oilas found in nature often contains considerablewater which must ordinarily be taken out before the oil is used andpreferably must be taken out before the oil is transported to any greatdistance from the poiiit of production. Thiswater is ordinarily carriedin the oil as an emulsion formed of isolated masses of water surroundedby oil, and these masses of water may be of any size from clearlyvisible globules to microscopically small particles. As water issomewhat heavier than the oil, gravity acts to draw the Water throughthe oil and emulsion, this setthug being resisted by the viscosity ofthe oil and bein expedited by heating the emulhas the eifect oflightening the 011 and reducing its viscosity. It is, therefore, commonpractice to roast emulsions, maintaining them at considerabletemperatures for some time to allow the water to settle. It is found,however, that the finer particles of water take an unduly long time tosettle out and this has led oil well operators to speak of the watercarried in these fine globules as trapped water, the water which readilysettle being spoken of as free water. While there is only a differenceof degree involved, this distinction will-be observed in the followingspecification, the free wa-. ter being that which will settle out ateconomical temperatures and in an economical time, and the trapped waterbeing that which will not settle out at economical temperatures in aneconomical time.

The principal object of my invention is to provide a process andapparatus for agwater. This I accomplish by the use "of electricdischarges through a body of the emulsion. The fact that such dischargeswill acf complish this object is well known, and va rious schemes havebeen proposed for so utilizing them. This is not diificult, as anyvoltage of suflicient magnitude to puncture a mass of the emulsion willin some degree cause such an agglomeration. The difficulty hes indevising an apparatus that can be used by any ordinary oil welloperator, which will have a large capacity and low cost, and in whichthe amount of electrical energy used will be small as compared to theoil treated. 'j

When an electrical potential of suflicient magmtude is impressed onelectrodes immersed in a body of emulsion, there is apparently anelectrostatic action tending to line the particles up in chains betweenthe electrodes, the separate drops or globules of each chain tendingtounite, due apparently to their. .propinqulty and the force with PatentedOct. 15, 1918.

which they are pulled into line. Agglomeration can apparently beaccomplished without the passage of any considerable current between theelectrodes or the breaking down of the natural high resistance pathoffered by the emulsion, and dehydration by this method is veryeconomical of electrical energy. If this lining up in chains is allowedto continue there is eventually a heavy discharge of electric current ora short cir-' cuit current flows between the electrodes through a lowresistance path formed almost,

entirely of water. This short circuit. our.-

rent is naturally very stable and persistent and quite wasteful ofelectrical energy. It has been the endeavor 'of certain previousinventors to devise apparatus and processes in which these chains werebroken up before they were entirely formed, thus, preventing theformation of chains completely short circuiting the electrodes andpreventing the flow of the heavy and wasteful short circuit current.These inventions have not been an unqualified success, due to the factthat such apparatus must of necessity work within a very narrow range.If the poten- 1 tial is too lowvery little dehydration takes place, andif too high, short circuit currents flow which use up large amountsofenergy f with no economical result. Such previous inventions aretherefore somewhat unsuited to oil well work as theyrequire skilledlabor for their operation.

They have, however, a more serious de.

feet in thatwhile the. dehydrating action is 7 very economical ofelectric energy, the ca-'- pacity in treated oil for any size of plantis small as compared to a plant operating in accordance with myinvention,

l have found that emulsions can be quite economically and easilydehydrated by wilfully forming low resistance paths or water betweenelectrodes immersed in the emulsion it the short circuit currents arenot maintained for too long a period, and my invention is directed tothe formation and breaking of such low resistance paths in a mass oremulsion. 1 form such paths by bringing my electrodes so close togetherthat a heavy current immediately flows, this current persisting for anappreciable time before the path is broken. By this means it is possibleto produce an apparatus which can be operated by any one without verymuch attention, and the capacity in oil treated is very high. I aminclined to believe that there is an electromagnetic action after theshort circuit is formed that materially helps in increasing thecapacity. This action is due to the natural attraction exertedbetweenpar- V allel paths carrying currents of the same polarity. T.believe that when my electrodes approach each other that a considerablenumber of chains are formed, these chains being more or less paralleland exerting a strong attraction on each other. By maintaining a heavycurrent in these chains for a short time after they are formed they arepulled together and form large masses of free water which will readilysettle out of the emulsion. While the large masses of water soagglomerated will settle out of the emulsion very rapidly, especially ifthe viscosity of the oil is low, there is still an appreciable timerequired for such settling, and ii the current is again applied to thesame mass or material without allowing for this settling, a waste ofcurrent will occur due to the flow of current through the agglomeratedfree water. in my invention It provide a lower electrode so arrangedthat the water can quickly get away from the path of the current and atthe same time I lift the mass of cleaned oil out of the path of thecurrent before again causing the current to ilow between the electrodes.As a result the material between the electrodes is largely changedbetween current flows, so that the current has constantly new masses toact upon. 'lhis lifting or the cleaned oil I accomplish by the use ofsuitably designed and actuated upper electrodes and l utilize themovement of these electrodes also to increase the length of the currentpath and eventually break the circuit. in an apparatus of this characterthe cost of the high potential transformer, when alternating current isused, is an important item and it would prove rather expensive toinstall transformer that would operate for only a short interval andthen idle during the time the upper electrode is moving to change thematerial to be treated. l orthe purpose.

or reducing the cost or the transformer and increasing the capacity oithe plant, I operate a number of treaters from one transformer, theupper electrodes of the diderent treaters being so set and actuated withrelation to each other that one treater has a heavy current flowingwhile the others are free from such currents, each treater operating inturn.

l have found that when an emulsion containing a large amount of water issubjected to the action of an electric current that large amounts ofwater are agglomerated and that the amount of dehydration that takesplace with a given current flow varies somewhat in proportion though notnecessarily in direct proportion to the amount of water in the emulsion.It is therefore economical to run the treaters in series, the amount ofwater in the oil diminishing in the successsive treaters until the lasttreater brings it.

down to a commercial value, which is ordinarily less than three percent. of the total.

It will therefore be seen that my invention is designed to dehydrateemulsions by the use of electric current; that is, it is designed toprovide an apparatus and process that may be operated by unskilled laborand that it is designed to provide an apparatus that will have a largeoutput per dollar of first cost. lit will further appear that this isaccomplished first by forming chains of water through which heavy shortcircuit currents pass, by breaking such chains as soon as a goodagglomeration takes place,and by removing the water and treated oil frombetween the electrodes before forming more chains. t will furtherappearthat these results follow from the use of a moving upper electrode whichserves to break the currents so set up and at the same time to move thematerial treated, so that the next flowot current has an entirely newmass of material to work on. it will further appear that additionaleconomies are efiected by the use of a series of treaters workingsuccessively onthe material and all connected to a single set ofelectrical apparatus.

Further objects and advantages will appear hereinafter or will beevident to one skilled in the art by an inspection of the drawing takenin connection with the following specification and claims.

in the drawings, which are for illustrative purposes only:

Figure lis a side'elevation of a plant embodying my invention, a portionthereof being broken away and shown in section.

Fig. 2 is an end elevation of the same plant.

Fig. 3 is a plan view, the lower portion or": the aparatus being omittedfor the sake l i OI that a greater or lesser number of compart- I mentscan be used if desired.

In the form'of dehydrator shown in these drawings, a tank 11 is shownhaving a steam coil 12 located in the bottom thereof and "having aseries of partitions 13 and 14 extending completely across it dividingit into four compartments 15.- The partitions 13 extend from the top ofthe tank to a point just above a line 88 which is near. the bottom ofthe tank 11 and which may be designated as .the water line, and thepartitions 14 extend from a point just above the top of the steam coil12,v which is considerably below the line 88, to a point just below aline 9 9 which may be designated as the oil line, this line defining thenormal level of the-oil or emulsion in the tankf An inlet pipe 16delivers emulsion to one end of the tank, and an outlet pipe 17 carriesaway the cleaned oil. A water outlet pipe 18, provided with a valve 19,projects up into the tank to a point just below the line 88.

Secured to the sides of the tank 11 and the partitions 14 and 13 arethelower electrodes 21.v These electrodes are preferably made of wirescreen and are-electrically connected to the tank vl1. Suspendedcentrally ineach able electrode 31. These upper electrodes of thecompartments 15, above the lower or stationary electrodes 21, is anupper'ormovare composed of a square frame 32 having upwardly projectingsides 33 to which are attached suspension rods 34. The bottom ofv theframe 32 is covered with av wire screen member 35 which forms a parallelsurfaceto the screen member of the lower electrode 21. It is between thetwo screen members 35 and 21 thatall the electrical currents flow forthe purpose of dehydration.

Each of the suspension rods 34 has 'secured at the upper end thereof aninsulator 36, these insulators having secured at their upper ends aguide-rod'37.

The guide rods 37 are connected by a crosshead 38 and slide in bearings39 formed in a cross head casting 40. The cross head casting 40 may beconsidered as being arranged in two pairs, each pair being connected bya crank shaft 41 which turns in central bearings formed in the crosshead casting 40. Secured to each end of each of the crank shafts 41 is acrank 42, the cranks on each end of any one shaft being set 180 degreesapart, and the two shafts being in such relation to each other that thecranks on one shaft 41 are 90 degrees apart from the cranks on the othershaft 41. Each of the shafts 41 is provided with a gear 43 which isdriven by a pinion 44, the pinion 44 being fixed to a drive shaft 45which is journaled in Suitable bearings formed in the cross head casting40 and in a bearing 46 which with the tank 11 and the various othermechanism is supported on a suitable wood'frame 47,

as shown in the drawings. Also supported on this frame are bearings 48which carry a shaft49 which drives the shaft 45 through a pinion 50 anda gear 51. The-shaft 49 is driven'through a pulley .52 and a belt 53from the pulley 54of a motor 55, or from any other suitable sourceoffpowe'r'. Each of thecranks .41 is connected to its respective crosshead 38 by a connection rod 56.

Each of the upper electrodes is connected through chains ,orrwires witha suitably insulated bus bar 61- which is connected to one side of thesecondary 63 of a suitable transformer generating sufiicient voltage toestablish a shortcircuit between the electrodes 21 and 31 when theelectrodes 31 are in their lower position. Thefcpposite side of thesecondary 63 is connected through a wire 66 with the tank 11 and throughthis tank with the lower electrodes 21.. The primary 64 ofthetransformer is connected through suitable fuses and. switches with a vconstant potentialdistribution system. A

resistance 65' may in some cases beconnected directly intothe circuit"of the primary ,64 for the purpose of the maximum value of the shortcircuit. I

Secured on hinges between the sides 33 of the upper electrodes 31' is apair of doors 71, these doors resting at their upper ends on a cross bar73. A. pair of rods 74 are-connected between the sides 33 so that theyallow the door to swing upwardand partly open, but strictly limit suchopening.

The method of operation of my invention is as follows:

The tank 11 being filled with the emulsion which it is desired. todehydrate, and a steady flow of emulsion being supplied to the tank '11through the pipe '16, the upper electrodes .31 are put in motion bystarting'the motor 55, this motor driving the shaft 49 through shaft49drives the shaft 45 through the pinion 50 and the gear 51, and theshaft 45 actuates the shafts 41 through the pinions 44 and gears 43. Aspreviously explained, the cranks 42 on each of the shafts 41 are set 180degrees apart, the cranks on one of these shafts being: set 90 degreesapart from the cranks on the other shaft. As a result, the four cranksare set 90 degrees apart around "the pulleys 54 and 52 of-the belt 53.The

the circumference of a circle. As the shafts 41 are rotated,-the motionof each crank 42 is tigansmltted through one of the connection rods 56to one the cross heads 88, this motion being transmitted to the properguide rods 37 which slide in the bearings oi the cross head castings 40.An up and down harmonic motion is therefore transmitted to each oi theupper electrodes 31, these electrodes alternately approaching andreceding from the lower electrodes 21.\ As each of the upper electrodes31 is connected to one side of the secondary '33 of the high tensiontransformer through the wires 64 61 and 62, and as the lower electrodes21 are all connected through the wire 66 to the other side of thesecondary 63, an alternating electrical potential is impressed betweeneach pair of the upper electrodes 31 andlower electrodes 21, and asthese electrodes approach very near together at the bottom of theirstroke, a heavy electrical discharge takes place therebetween, thisdischarge being formed through water chains which are formed andagglomerated into large masses. These large masses immediately fallthrough the meshes of the lower electrodes 21 and settle in the bottomof the tank, becoming incorporated with the body of water which alwayslies in the tank below the line 8-8. Water me be continuously taken 0diromthis body of water by means of the water outlet pipe 18 by asuitable manipulation of the valve 19, or it may be automaticallydrained of by any one of several means well known in the art.

as soon as a low resistance path consisting of water chains has beenformed between the upper electrode'Sl and the lower electrode 21 in anycompartment 15, the chains are elongated by the subsequent upwardmovement of the electrodes 31, this upward movement being quiteconsiderable as compared to the initial gap. This lengthening out of thecurrent path greatly increases the resistance of the path, so that asthe upper electrode 31 in an adjacent compartment reaches its lowerposition, the current reestablishes new low resistance paths and chainsin that-compartment, and the current ceases in the compartment in whichthe upper electrode has made its upward motion. As a result, the chainsare formed in each of the compartments successively, these chains beingdrawn out and agglomerated by the movement of the electrode and thecurrent continuing to fiiowv until the upper electrode in anothercompartment has approached suficiently to allow the current to form amuch lower resistance path. As a result, each of the compartmentsmomentarily receives practically the full power delivered by thesecondary 63, the remaining compartments being comparatively inertduring this time. The upper electrodes 31 not only serve to draw out thearc,but due to the operation of the doors 71 th y act as pistons to drawfresh charges of emulsion between the electrodes during the up stroke ofthe upper electrode 31., During this up-stroke the doors 71 are closed,resting against the cross bar 73, and fresh emulsion is drawn into thespace betwwn the electrodes from the sides and ends of the tank and tosome extent upwardly through the lower electrode 21. AS soon as any oneof the upper electrodes 31 starts on its downward path, the doors 71open until they strike the rods 74, and the previously treated oil whichhas collected inside the upper electrode is released into the top of thetank. in other words, the upper electrodes 31 pick up a considerablequantity of the already treated material on the up-stroke and release itthrough the doors into the top of the tank on the down-stroke, so thatwhen the upper electrodes reach a point at or near the bottom of theirtravel, and new chains are ormed, these chains are formed through reshemulsions and not throughthe same mass of material which was treatedupon the previous flow of current.

The emulsion in entering the tank through the oil inlet pipe 16 isforced to how downwardly to a point just above the top of the water inthe bottom of the tank by the first of the partitions 13. This emulsionthen passes upwardly through the lower electrode screen members 21 ofthe first compartment and is subjected to the dehydrating action or? thecurrent, finally passing over the partitions 14 and flowing downwardlhetween the artitions 13 and it to a point in the neat compartment 15just above the water line 88, and repeating this movement through thesuccessive compartments. By introducing the emulsion into the bottom ofthe compartments 15, so that the general direction or flow through thecompartment is upward, we allow the masses of free water to settle outin each individual ompartment and join the water in the bottom of thetank ll. At the same time, the liquid in the top of each oi thecompartments is very considerably drier than the material in the bottom, and by making the partitions i l in the shape shown we are able toslnim ofi" from the top of each or the compartments 15 the clean oil,mixed with a certain proportion of emulsion, with perhaps smallquantities of free water. The amount of water present in the liquidcontinually diminishes as the oil flows successively through the variouscompartments 15, so that the oil which is finally taken 05 from the topof the last compartment, by the pipe 17, contains very small quantitiesof water in any form, the dehydration being practically complete.

The water in the bottom or the tank acts as 'a seal for the bottom orthe various partitions 1 preventing emulsion or oil from passing aroundthe thereof. By stopping the partitions above. th

menace bottom of the tank 11 and allowing an open space thereunder, I amable to use a single heating coil and a single water outlet pipe 18. Byimmersing the heating coil 12 in this body of water, there is' no dangerof burning the oil due to its contact with hot steam pipes, and it ispossible to maintain the temperature of the contents of the tank 11 atany desired degree. In some cases, it is desirable to heat the emulsionbefore delivering it'to the tank 11, and in some cases it is desirableto deliver the oil from the ipe 17 into an auxilia settling tank in wich the liquid is maintained at considerable temperatures for thepurpose of allowing a further settling of the free water. In otherwords, in some cases it is economical to run the apparatus shown in thedrawings at such a rate that onsiderable free water is carried 011'through the pi e 17. In most cases, however, it is possi le to settleout sufiicient water from the compartments 15 to bring the efiiuentpassing throu h the pipe 17 down to the desired degree of dryness.

As we-wilfully form heavy short circuits in the various compartments 15,variations in the quality of the emulsion supplied do not in any wayaflect the; electrical operation of the plant. In other words, if we aresupplying a liquid which consists wholly of emulsion, and this emulsionis cut down by changes in 1production to 25 er cent. of its original vaue, it does not a ect the operation of the apparatus, short circuitsstill being formed and the dehydration still continuing. In thisparticular, my invention difl'ers very materially from those in whichthe apparatus must be re lated in such a manner as to prevent t eformation of chains, as in such cases this regulation must be constantlmade to suit an varying conditions of t e liquid supplie By causingthese heavy short circuits, and by pulling them out mechanically in thetreater, a comparatively small apparatus has a large capacity, so thatthe first'cost of a treater for handlin quite low. t the same time, byrunning the treater at a suitable speed, and by my arlarge amounts ofemulsion is rangement which provides for successive action in thedifi'erent compartments, the current economy is still quite low.

I claim as my invention 1. A process of dehydrating emulsions whichconsists in im ressing an electrical potential on electro es immersedin. the emulsion; causing the electrodes to approach each other to asufiicient degree to cause water chains to be formed between theelectrodes through which heavy short circuit currents can flow; andthereafter breaking said chains and interrupting said currents byseparating said electrodes.

2. A process in which a plurality of sets of electrodes operating as setforth in claim (1) are used, said electrodes bein so arranged that onlyone set of electro es is in :current carrying relationship at any giventime.

3. A process in which electrodes operating as set forth in claim (1) areso arran ed that the separation and approach of t e electrodesconstantly changes the material to be acted on.

4. An apparatus for dehydrating emulsions comprising a containingVessel; a lower electrode fixed in said containing vessel; an upperelectrode suspended over said lower electrode and movable verticallywith relation thereto; means for impressing an elec:

tromotive force between said electrodes; and

means for movin said upper electrode vertically toward and away fromsaid lower electrode.

5. An apparatus as specified in claim 34) in which the upper electrodeis provi ed with a valve so that the up and down movement of theelectrode produces a unidirectional trend to the movement of the oil.

6. An apparatus as specified in claim (4) in which the lower electrodeis provided with perforations through which the agglomerated water mayescape.

In testimon whereof, I have hereunto set my hand at os Angeles,California, this 29th day of March, 1917.

